An inflatable belt apparatus with an inflatable belt of this type has been described in Japanese Patent JP-A-2001-260807. In JP-A-2001-260807, the inflatable belt (webbing) of the inflatable belt apparatus comprises a stretchable inflatable area in which a gas bag is accommodated and a non-inflatable area which is wound up by a retractor. The gas bag accommodated in the inflatable area is inflated by gas supply in the event of a vehicle collision, whereby a vehicle occupant is restrained via the inflatable belt which is thus inflated.